CSLB C-33 Painting & DecoratingSafetyMedium

A worker is using a paint sprayer with highly volatile, flammable solvents. Which type of electrical equipment is required in the immediate work area to prevent ignition of flammable vapors?

  1. AHeavy-duty industrial-grade electrical equipment.
  2. BStandard residential-grade electrical equipment.
  3. CGround-fault circuit interrupter (GFCI) protected equipment.
  4. DExplosion-proof or intrinsically safe electrical equipment.
Show answer & explanation

Correct answer: D. Explosion-proof or intrinsically safe electrical equipment.

When working with highly volatile, flammable solvents, the risk of ignition from electrical sparks is significant. Explosion-proof or intrinsically safe electrical equipment is specifically designed to prevent sparks or heat from igniting flammable atmospheres, making it essential in such hazardous locations. Standard, GFCI-protected, or heavy-duty equipment does not provide this level of protection against flammable vapors.

Why the other options are wrong

  • A. Heavy-duty equipment may be more durable but does not inherently prevent ignition in flammable atmospheres.
  • B. Standard equipment can easily create sparks capable of igniting flammable vapors.
  • C. GFCI protects against electric shock to personnel, not against ignition of flammable atmospheres.

Explosion-Proof Electrical Equipment

Electrical equipment designed to safely operate in hazardous locations where flammable gases or vapors may be present, by preventing internal sparks from igniting the external atmosphere.

  • Enclosures are strong enough to contain an internal explosion.
  • Prevents ignition of the surrounding atmosphere through flame paths.
  • Required in classified hazardous locations (e.g., Class I, Division 1 areas).

Memory trick: Flammable air needs a spark-free affair.

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